49 一個球,圓溜溜, 一個球 圓溜溜 夜間人人不見, 夜間人人不見 日間家家都有。 日間家家都有 猜 一 種自然現象 猜一種自然現象 Guess what? A ball, round, it rolls along. At night, no one sees it. By day, it is there for every house. ( A natural phenomenon ) 60